AppliedModernization42 min
APIs and REST on z/OS
How mobile apps and websites talk to CICS, IMS and DB2 programs through REST APIs: HTTP and JSON in plain terms, mapping copybooks to JSON, exposing and calling APIs, and keeping them secure.
What you will be able to do
- Explain HTTP methods, status codes and JSON using mainframe comparisons
- Map a COBOL copybook to a JSON payload and spot the conversion traps
- Describe how z/OS Connect and CICS expose existing programs as REST APIs
- Explain how a COBOL program calls an external API
- List the security and operational checks a production API needs
Lessons
- REST in plain termsA REST API lets one program ask another for something over HTTP, the same protocol web browsers use.
- From copybook to JSONMainframe programs exchange fixed-layout records described by copybooks; APIs exchange JSON with named fields.
- Exposing CICS and IMS programs as APIsYou do not rewrite a working CICS or IMS program to give it an API. A gateway on z/OS receives the HTTP request, converts the JSON into the program's input structure, calls the…
- Calling external APIs from COBOLAPIs work in both directions. A COBOL program can call a service elsewhere — a fraud check, an address lookup, a cloud service — by building JSON, sending an HTTP request, and…
- Securing and running mainframe APIsAn API opens the mainframe to callers you have never met. Securing it means encrypting traffic, proving who the caller is, mapping that identity to a RACF user so existing access…
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Free account, 90 quiz questions for this subject.